Hint the parameter of the regex realdom.
Add the `hoa realdom:reflection` command.

Example:

    $ hoa realdom:reflection string
    Realdom [Hoa\Realdom\String] string {
        [#0 required] Constinteger|Conststring codepointMin = 32;
        [#1 required] Constinteger|Conststring codepointMax = 126;
        [#2 optional] Integer                  length;
    }